Conventionally, when a high voltage discharge lamp (for example, metal halide lamp) which needs a high voltage at startup is used as a vehicle headlamp, a high voltage transformer which outputs a high voltage have been used, as disclosed in Japanese Laid-open Patent Application Publication No. 8-130127 (Patent Literature 1), for example.
The conventional high voltage transformer, as disclosed in Japanese Laid-open Patent Application Publication No. 8-130127 (Patent Literature 1), is constituted by a core, a hollow cylindrical shaped spool into the hollow portion of which the core is inserted, a secondary winding wound around the outer periphery of the spool, a casing made of a resin covering the spool being wound with the secondary winding, and a primary winding being inserted into the casing. The core, the spool and the secondary winding are housed in the casing, covered with a filled resin, and are fixed and integrated. Further, it is disclosed in Japanese Laid-open Patent Application Publication No. 8-130127 (Patent Literature 1) that by inserting the both ends of the primary winding being disposed on the casing of a printed circuit board, the core, the spool, the secondary winding, the casing and the printed circuit board are integrated, and the high voltage transformer is configured.